Reactive polymers and process for the production thereof

ABSTRACT

A STARTING POLYMER OF AN OLEFINICALLY-UNSATURATED COMPOUND AND CONTAINING MORE THAN ONE HALOGEN PER POLYMERIC MOLECULE, PARTICULARLY AS AN ALLYLIC HALOGEN GROUP, IS TREATED WITH A MULTIFUNCTIONAL AGENT TO FORM A POLYMER WHICH IS THEN CURABLE WITH ISOCYANATE. THE MULTIFUNCTIONAL AGENT HAS AS A FIRST FUNCTIONAL GROUP A TERTIARY AMINE OR A HYDROCARBYL OXIDE OF AN ALKALI METAL OR MERCAPTIDE OF AN ALKALI METAL; THE AGENT HAS AT LEAST ONE OTHER FUNCTIONAL GROUP WHICH IS LESS ACTIVE THAN THE FIRST GROUP AND HAS A LABILE HYDROGEN ATOM CAPABLE OR REACTING WITH ISOCYANATE.

United States Patent 3 639,339 REACTIVE POLYMERS AND PROCESS FOR THEPRODUCTION THEREOF John Beaton and Douglas C. Edwards, Sarnia, Ontario,

and Richard Helmut Wunder, Corunna, Ontario, Canada, assignors toPolymer Corporation Limited, Sarnia, Ontario, Canada No Drawing. FiledMay 20, 1968, Ser. No. 730,662 Claims priority, application Canada, June28, 1967,

944,149 Int. Cl. C08d 5/02; C08f 27/02, 27/08 US. Cl. 260-47 1 ClaimABSTRACT OF THE DISCLOSURE A starting polymer of anolefinically-unsaturated compound and containing more than one halogenper polymeric molecule, particularly as an allylic halogen group, istreated with a multifunctional agent to form a polymer which is thencurable with isocyanate. The multifunctional agent has as a firstfunctional group a tertiary amine or a hydrocarbyl oxide of an alkalimetal or mercaptide of an alkali metal; the agent has at least one otherfunctional group which is less active than the first group and has alabile hydrogen atom capable of reacting with isocyanate.

This invention relates to reactive polymers of olefinically unsaturatedcompounds. In particular, it relates to the production of low molecularWeight, terminally reactive polymers and their reaction withisocyanates.

It is well known to produce hydroxy terminated polymers of olefinicallyunsaturated hydrocarbons, such as butadiene and styrene, and react themwith organic polyisocyanates to produce higher molecular weightchainextended soluble polymers or crosslinked insoluble polymers. Oneprocess of preparing such polymers is described in Canadian Pat. 653,783issued Dec. 11, 1962; this process involves polymerizing olefinicallyunsaturated aromatic hydrocarbon in an anhydrous system using anioniccatalyst such as alkali metals or alkali metal hydrocarbyls, andcontacting the product of polymerization with a carbonyl compound andthen, a proton donor. The above process is limited to monomers which areinert to anionic catalysts; extreme precautions are required toeliminate moisture and other poisons in the polymerization andtermination steps, if difunctional polymers are desired; randomcopolyrnerization of comonomers of different types is difiicult; and thenumber of variations in the structure and composition of e.g. hydroxylterminated polymers is rather limited.

It is an object of this invention to provide a new process of producingreactive polymers. Another object is to provide new improved reactivepolymers of olefinically unsaturated compounds.

The present invention is based on the discovery that polymers ofolefinically unsaturated compounds containing more than one halogen perpolymeric molecule, for example two halogens in terminal positions, canbe reacted with a multifunctional agent to form a polymer which isreactive with isocyanate, said agent containing a first functional groupcapable of reacting with one of said halogens and at least one otherfunctional group having a labile hydrogen atom and being less activethan said first group to said halogens.

The objects of the present invention are achieved by a process ofproducing an isocyanate-curable polymer of an olefinically unsaturatedcompound which comprises treating a low molecular weightisocyanate-non-reactive polymer of said compound, a major proportion ofmolecules of said polymer containing more than one halogen "ice atom,with a multifunctional agent having a first functional group and atleast one other functional group, said first functional group beingselected from tertiary amines, hydrocarbyl oxides of alkali metals andmercaptides of alkali metals and being capable of reacting with one ofsaid halogens to produce a bond between said polymer and said agentthrough a hetero atom selected from nitrogen, oxygen and sulphur, saidother functional group being less active than the first group and havinga labile hydrogen atom capable of reacting with isocyanate.

This invention also provides a novel isocyanate-curable polymer of anolefinically unsaturated compound, a majorproportion of molecules ofsaid polymer containing more than one functional group, said functionalgroup being attached to polymer molecule through a hetero atom selectedfrom nitrogen, oxygen and sulphur, and having a labile hydrogen atomcapable of reacting with isocyanate.

One polymer that can be used in the process of this invention is a lowmolecular weight material having a molecular weight at least about 1000.Above this lower limit, the molecular weight may vary widely, althoughit is desirable for some purposes that the polymer is liquid andpourable, preferably at room temperature, that is, that it has a bulkviscosity of not more than 5000 to 10,000 poises at 25 C. However, it iswithin the scope of this invention to use higher molecular weightpolymer, the bulk viscosity of which has been reduced, if desired, witha compatible plasticizer.

The starting polymer is characterized by the presence of more than onehalogen per molecule in the majority of the molecules. The halogen maybe a halogen attached to a saturated carbon atom which is in the alphaposition to an olefinic or'carbonyl carbon atom. A preferred class ofhalogens are in the form of allylic halide groups having the formula-C=C(|]X l l l in which X is a halogen atom. Halogen atoms attached tosaturated hydrocarbon chains may also be used under some conditions, forexample, when brought in contact at elevated temperatures withmultifunctional agents having such functional groups as alkoxides ofalkali metals. The halogen atom may be selected from chlorine, bromineor iodine. It is preferred that the halogens are attached to thepolymeric molecules in terminal positions, i.e. at the ends of linearchain molecules and, if the molecules are branched, at the end ofbranches. In other words, the preferred polymer contains molecules withtwo or more terminal allylic halide or haloalkyl carbonyl groups.However, the presence of allylic halide groups or other halogen groupsin the middle portions of the chain molecules is not detrimental. Thepolymer is a homopolymer or a copolymer of two or more polymerizableolefinically unsaturated compounds and may be prepared by a free radicalpolymerization. Unsaturated hydrocarbons are the the preferred compoundsused in the preparation of the polymer, although polymerizable monomerscontaining oxygen, nitrogen and/or chlorine atoms in addition to carbonand hydrogen atoms can the used provided they are not active accordingto the Zerewitinofi-test as described in J.A.C.S. 49, 3181 (1927). Thepreferred polymers used in this invention are low molecular weightpolymers of diolefinic aliphatic hydrocarbons containing 4 to 8 carbonatoms such as butadiene-1,3, isoprene, pentadiene-l,3,2,3-dimethylbutadiene, and best results are obtained with polymers ofbutadiene-1,3, with or without a minor amount of copolymerized vinylcompounds such as styrene, acrylonitrile, alkyl acrylate and others.Depending on the molecular weight of the polymer, the type and thenumber of halogen atoms per molecule, the halogen content of the lowmolecular weight polymer falls within the range of 1-15 weight percentand preferably within the range of 15-10 weight percent.

The low molecular weight polymer suitable for use in this inventionmaybe prepared by various processes. One such process is a directpolymerization of monomers in the presence of halogen-containingmodifiers such as described in French Patent 1,488,811. It is alsopossible to produce such polymers by post-polymerization modificationsuch as halogenation of unsaturated polymers, oxidative halogenation ofsaturated polymers or degradative halogenation of solid polymers, underconditions such that at least two halogens are produced in a polymericmolecule.

The multifunctional compound which is reacted with thehalogen-containing polymer contains a first functional group and atleast one other functional group. The first group is selected from atertiary amine group, a mercaptide and a hydrocarbyl oxide of an alkalimetal. For example, it can be an aromatic or aliphatic amine, sodiumalkoxide or potassium mercaptide group. The tertiary amine group is agroup where R and R are each hydrocarbon groups, generally loweraliphatic hydrocarbon groups containing up to 6 carbon atoms, preferablymethyl or ethyl or the R and R groups are joined to form a ring of 3, 4,or more carbon atoms, thereby forming a heterocyclic ring with thenitrogen atom.

The other functional group is less reactive towards halogen than thefirst functional group but contains a labile hydrogen atom capable ofreacting with isocyanate. It may be a primary or secondary amino, amido,hydroxyl, mercapto, carboxyl, thiocarboxyl, sulpho or sulphino group.Preferably, the multifunctional compound is a low molecular weightcompound with the functional groups separated by at least one carbonatom. The portion of the molecule between the first and other functionalgroups is generally an aliphatic hydrocarbon chain preferably containingup to carbon atoms, or an aromatic nucleus, preferably benzene. Thepreferred difunctional compounds contain at one end a tertiary aminegroup or a mercaptide group and at the other end a different functionalgroup such as OH, SH, COOH, CSOH, COSH, CSO3H, CSOzH, NHz, CONHg- Thepreferred other functional groups are hydroxyl, carboxyl and primaryamino groups.

Examples of difunctional compounds containing at one end a tertiaryamine group are 3-diethyl amino-propanoll, N,N-diethy1 glycine,N',N'-dimethyl trimethylene diamine-1,3 N,N-diethyl amino ethane thiol,N,-N-dimethyl amino m-phenol, N,'N-dimethyl amino p-benzoic acid. Arepresentative example of polyfunctional tertiary amine istriethanolamine. The difunctional compounds containing a mercaptidegroup are prepared by reacting mercaptan compounds such as fi-mercaptoethanol, p-amino benzene I thiol, or fi-mercapto ethyl amine with alkalimetals in I the presence of a low molecular weight alcohol containing upto 8 carbonatoms. The alkali metals include lithium, sodium or potassiumand ethanol, propanol and butanol are the typical alcohols that can beused in the reaction. Instead of the mercaptan compounds, alcohols suchas amino ethanol, aminobenzyl alcohol can be reacted with alkali metalsto produce a difunctional agent containing reactive hydrocarbyl oxidegroup.

The reaction between the halogen-containing polymer as described aboveand the multifunctional compound may be conducted in solution or bulk orlatex. In the solution technique, the halogen-containing polymer isdissolved in .4 boiled or refluxed until the reaction is complete. Thesolution may be filtered and then the polymeric product is recovered byprecipitation, generally in methanol or in a mixture of acetic acid inmethanol. An antioxidant is generally added to the product to preventoxidative degradation on standing.

The product of the above reaction is an isocyanatecurable polymer of anolefinically unsaturated compound. The predominant and main part of thepolymer consists of the polymerized units of said compound which arelinked together by carbon to carbon bonds. These polymerized units ofcompounds such as butadiene, styrene or ethyl acrylate are free oflabile hydrogen atom and not capable of reacting with isocyanate. Theyhave more than one functional group in the terminal position joined tothe main part of the polymer through a hetero atom selected fromnitrogen, oxygen or sulphur. Polymer molecules containing two functionalgroups having a labile hydrogen atom capable of reacting with isocyanateare preferred, although polymers with several such groups in theterminal positions can also be used in the reaction withpolyisocyanates. The reactivity of the groups is not restricted to thereaction with isocyanate; they can be condensed with other reactivegroups to form, for example, ester or amide bonds. When the polymer isdifunctional, that is, contains two functional groups per molecule andis reacted with diisocyanate, a chain-extended higher molecular weightpolymer is obtained. This chainextended polymer may be worked on rubberor resin proc- V linkage.

The reactivity of the reactive polymer of this invention is controlledby the selection of a multifunctional agent having the desiredfunctional group. This functional group being removed from the mainpolymer part by a hetero atom of the first functional group is notaflected by the structure, type of bonds and substituents in themonomeric units in the main part of the polymer as it is in the case ofthe prior art difunctional polymers. In contrast to polymeric glycols ordiamines of the prior art, the isocyanate-curable polymers of thisinvention are remarkably insensitive to varying proportions ofpolyisocyanate.

The reactive polymers of this invention are preferably low molecularweight polymers and most preferably pourable polymers so that they canbe easily blended with polyisocyanates or other crosslinking agents, andeasily shaped and cured. The reaction of dihydroxyl polymers ofolefinically unsaturated compounds with polyisocyanates is well known.The use of polyurethanes and polyureas in the rubber and resintechnology is also known so that a detailed description seems to beredundant.

The invention is further illustrated by, but not limited to, thefollowing examples. In these examples, all parts 3.5 grams of3-diethylamino-propanol were dissolved in 15 mls. of ethanol. 20 gramsof a bromine terminated polybutadiene produced according to the processdescribed in French Pat. 1,488,811 and having an intrinsic viscosity intoluene of 30 C. of 0.30 were dissolved in mls. of toluene. Theethanolic solution was then added with vigorous stirring to the toluenesolution. The resulting mixture was heated to boiling and then allowedto cool. The product produced was recovered by precipita tion in anexcess of methanol. A quantitative yield of product was obtained. Thepolymer so produced was purified by precipitation from toluene intoacetone. The purified polymer, Which had an intrinsic viscosity intoluene The above procedure was repeated except that fi-mercapto ethanoland B-mercaptoethylamine, respectively, were used in place ofp-aminobenzenethiol and, in each case, 2.0 gms. of the [3 compound wereused with 1.0 gm.

at 30 C. of 0.76, was then dissolved in toluene and vary- 5 of sodium.ing amounts of a 4% solution of toluene diisocyanate in The polymermodified with B-mercaptoethylamine cured toluene were added. Thesolutions were stirred and poured So fast that poured films could not beproduced but hand onto glass sheets. The films produced afterevaporation tests indicated that the vulcanizates had high tensile ofsolvent were allowed to cure for a week at room tem- Strehgth- TheProperties of the Other fi Wn in perature and at the end of that timewere submitted to Ta l III. stress/strain testing. The properties of thefilms are presented in Table I. TABLE 111 TABLE I Toluene polyisoeyanateToluene diisocyanate (parts (parts per 100 per 100 parts polymer) partsploymer) Vulcanizate property 4.0 5.6 7.2 8.0 Modifying compoundVulcanlzate property 4.8 6.4 7.2

Tensile strength (p.s.i.) 269 245 263 265 Tensile strength (p.s.i.) 610750 1, 100 Elongation (percent) 360 265 255 260p-AminobenzenethioL..{Elongation (percent) 150 160 210 Modulus at 100%elongation (p.s.i.) 57 72 83 70 100% modulus (p.s.i.) 450 520 570 M t th1 {giansiletstrength (ps.i.) $30 Z40 EXAMPLE n loti hiidh tfitoii:i31::493 550 533 A solution of 4.2 gms. of N,N-diethylglycine hydrochloridein 15 mls. of ethanol containing 0.55 gm. of A com amtive e ri Ht w r dt sodium was vigorously stirred with a solution of 20 gms. 01 h i g meon W1 i d of the bromine terminated polybutadiene of Example I. g gg 3:a eimma f 3 t: i ac The mixture was heated to boiling and refluxed forone slowl g 2 0 f a i um hour. The solution was then allowed to cool andthe prodd fil h e ylsogyana e not was recovered y Precipitation in anexcess of a 20% i 5 z g a 61181 Strengt m t e range solution of aceticacid in methanol. The polymer obtained Ween an in quantitative yield waspurified by precipitation from toluene into acetone. The purifiedpolymer was then dis- EXAMPLE V solved in toluene and a solution ofvarious quantities of A 0% l i f an l i bromine terminated l toluenednsocyanate in solution added. The solution was butadiene was preparedas described in French Pat Stirred and the Whole pe Onto a glass sheet-The hhh 1,488,811 by polymerizing to about 80% conversion. 16 producedafter evaporation of solvent was allowed to cure parts per 100 parts fbutadiene monomer f 1 for a Weetf and the end of that tlme wassflbmltted to amino propanol were then added to the emulsion and theStress/Strain testlhg- The results are Shown 111 Table emulsion wasmaintained at 130 F. for 75 minutes. The TABLE II 40 polymer wasrecovered from the latex and cured with 5.6 parts of toluenediisocyanate by the method of Exam 1e I. $rt s i idhh The cured producthad a tensile strength of 675 ps5, an Parts Polymer) elongation of 350%and a modulus at 100% elongation Vulcanizate property 4.0 6.6 8.0 Of r11:7 PI-JS-id e a ove proce ure was repeated, except that 24 parts tf fiftififi iihhiP133::::::::::::3:13:33: 33? it? it 4.5 or 3-diethy1aminopropanol were added to the latex. The Modulus at 100% elongatmn 230 33641 cured product had a tensile strength of 722 p,s,i an 1 EXAMP HI of330% and a modulus at 100% elongation of 644 1.04 gms. of dimethylaminometa-phenol were mixed The above examples indicate that terminallyactive with 20 gms. of the bromine terminated polybutadiene of productscan be produced from active halogen containing Example I. The mixturewas left for 1 week at room tempolymers and these terminally activepolymers can be perature in a closed container to allow time forcomplete cured to elastomeric products having satisfactory stress/reaction. At the end of this time, the container was opened straincharacteristics. and a semi-solid mass was found therein. The mass,which had an intrinsic viscosity in toluene at 20 C. of 0.63, wasEXAMPLE VI taken up in toluene and 4.8 gms. of toluene diisocyanatedissolved in toluene were added. A film of cured product A hquld bromlhetefmlhated P y of ethyl aetylate was obtained as outlined in Example I.The film had a was l b the emulsion Polymerization of ethyl tensilestrength of 260 p.s.i., an elongation of 300% and acrylate 1n the P e 0f15 Parts/100 Parts of monomer a modulus at100% elongation of 210 Psi 0of carbon tetrabromlde using the method described in French Pat.1,488,811 for polybutadiene. The polymer EXAMPLE IV was cogulated anddried; 100 grams of it was dissolved in A solution of 3.0 gms. ofp-aminobenzenethiolin 15 mls. t uene to give a 25% solution, which wasthen mixed of ethanol containing 0.75 gm. sodium was mixed with a h aSolution of 12 grams of KOH in 66 grams of solution of 20 gms. of thebromine terminated polybuta- Ylehe gtyeol and the miXtllre Was boiled f5 minut sdiene of Example I. The mixture was heated to boiling Theproduct was precipitated and purified with pentane and a precipitatewhich was formed was removed by filtraand acetone and finally dried at60 C. tion. The polymer was coagulated in methanol and purified Theresulting liquid product was mixed in bulk, as well by precipitationfrom toluene solution into acetone. The as in solution in methyl ethylketone, with 5, 10 and 15 purified polymer was redissolved in tolueneand various 70 parts/100 parts of polymer, respectively, of apolyisocyquantities of a polyisocyanate, containing 32% isocyanate anateavailable under the trade name Mondur R. All the (available under thetrade name Mondur R), was added mixtures satisfactorily cured to formsolid rubbery matein solution. The solutions were stirred and pouredonto rial having high tensile strength. glass sheets. Films of curedproduct were obtained as out- What is claimed is: lined in Example I. 1.A process of producing an isocyanate-curable polymer of an olefinicallyunsaturated compound which comprises treating a liquid compositioncomprising a low molecular Weight isocyanate-non-reactive polymer ofbutadiene-l,3, said polymer having a molecular weight of at least about1000, a major proportion of molecules of said polymer containing interminal positions more than one allylic bromine atom in the terminalposition, with a multifunctional compound selected from the groupconsisting of 3-dia1ky1 amino-propanol-l, N,N-d'ialkyl glycine, N',N'-dialkyl tn'methylene diamine-1,3, N,N-dialkyl amino ethanethiol,N,N-dia1ky1 amino m-phenol, N,N-dialkyl amino p-bcnzoic acid, triethanolamine.

References Cited UNITED STATES PATENTS JOSEPH L. SOHOFER, PrimaryExaminer W. F. HAM'ROCK, Assistant Examiner US. Cl. X.R.

